1. Field of the Invention
The invention is directed to a portable laser emitter which emits in at least two axial directions, including the plumb, and which is self-leveling with respect to the gravitational force, particularly to a plumb emitter or a multi-axis laser emitter.
2. Description of the Prior Art
The invention is limited to portable plumb emitters or multi-axis laser emitters with visible point beams or cross-shaped beams which are immovable in the self-leveled state which is effected entirely by gravitational force. They are used particularly in the construction industry for a stable determination with respect to the coordinate origin and coordinate direction of a temporary local Cartesian coordinate system. Accordingly, the invention is explicitly not directed to laser emitters with actively movably deflected laser beams such as, for example, rotary lasers, because the latter have insufficient stability over the long term.
German Utility Model DE20100041U discloses a plumb emitter which is oriented to the earth's gravitational field and which has an upwardly directed vertical point beam. The laser beam source is arranged below the tip bearing.
European Publication EP0715707 discloses a multi-axis laser which is oriented to the earth's gravitational field. Two of the five point beams in each instance define a horizontal and vertical plane, respectively, of a half-space.
According to U.S. Pat. No. 5,539,990, instead of point beams, beam bundles which are fanned out horizontally and vertically in a flat manner are emitted on multiple axes as cross-shaped beams. In the following, both beam variants are embraced by the expression ‘axial beam’.
According to U.S. Pat. No. 5,144,487, a two-axis gimbal joint is arranged on top in the portable housing in a five-beam multi-axis laser emitter. The laser beam source, arranged at the bottom, and the beamsplitter are point-supported at the two-axis gimbal joint and movably suspended in a self-leveling manner by gravitational force. When the multi-axis laser emitter is appropriately mounted at a reference point on a roughly leveled building area, the projected plumb point of the plumb beam of the Cartesian coordinate system on the building area wanders away from the reference point by a correction distance depending on the self-leveled correction angle. If the correction distance is not sufficiently small, the multi-axis laser emitter must be displaced and must level itself again.
Further, according to European Publication EP1026476, in a two-beam multi-axis laser emitter without a plumb beam, a two-axis gimbal joint is arranged at an axis which projects by approximately one half of the height of the housing. Two laser beam sources, which are arranged at the bottom and are perpendicular to one another, are point-supported at the two-axis gimbal joint and are movably suspended in a self-leveling manner by gravitational force.